Building Computer Problems

Hi everyone, I'm building a computer for the first time and I've run into problems, so decided if you guys could help. I think I have everything connected correctly, but when I try to power it up, only a red light on the motherboard turns on. Are there any simple explanations for this or might it have to do with the specific parts I'm using?

Well I got it working. I guess. I dis-assembled and re-assembled it and it worked. It comes up with a reboot or select proper boot device screen now. I tried booting from cd drive with windows but it doesn't work. Maybe it's the cd?